Woburn, MA – November 25, 2019 – Kaspersky research revealed that the monthly number of affected users has grown from 1,722,545 in January to 5,544,530 in September 2019. In total, during the first nine months of 2019, Kaspersky products protected more than 14 million users from attempts to allow websites to show unwanted notifications. Given that essentially every web user is a potential victim, this threat, although unsophisticated, requires additional attention.

Browser push notifications were introduced several years ago as a useful tool that kept readers informed with regular updates, but today they are often used to bombard website visitors with unsolicited advertisements or even encourage them to download malicious software. Useful, user-friendly features, such as push notifications, are easy-to-use instruments for scams based on social engineering techniques, and therefore their growing popularity is not entirely unexpected. In light of the recent calendar invitations scam detected by Kaspersky, the company’s experts decided to dive deeper into push notification scams and phishing to find out how this tool can be abused.

Since a user’s consent is required in order to start sending notifications, attackers have come up with multiple, often out-of-the-box ways to trick and force people to sign up for subscriptions. The detected options include:

• Passing subscription consent off as another action, such as a CAPTCHA
• Switching the “accept” and “decline” buttons on subscription alerts mid-action
• Showing notifications from phishing copies of popular websites
• Showing fraudulent subscribe pop-ups on websites

Number of Kaspersky products users that have been hit by ad and scam push notifications, January – September 2019

After gaining a user’s consent, attackers start bombarding them with messages. The least harmful (and yet the most popular) options are clickbait ads on sensitive social topics, while others include scam notifications – like lottery wins, offers of money in exchange for completing a survey or something similar. Schemes that are more sophisticated are targeted at milking money out of users using phishing techniques.

An example of a phishing notification impersonating a Microsoft Windows system update

A common scheme uses messages disguised as system notifications, such as virus infection alerts. These redirect users to phishing copies of trusted websites and then prompt users to download various paid “PC cleaning” utilities. However, the potential of push notifications being used for such scams is not limited to just that.

“We have seen a rise in push notifications being abused, as attackers continue to creatively adapt new technologies in order to trick users. Because this feature is so widespread and easy to take advantage of through social engineering schemes, we have seen a rapid growth in the number of affected users. Push notifications are a very useful tool for users that help them stay on top of important things that interest them. Yet, as with anything on the internet, users have to remain attentive and cautious when interacting with pop-ups and only allow push notifications if they are completely sure the alerts are useful and come from trusted sources,” said Artemy Ovchinnikov, security researcher at Kaspersky.

To avoid receiving annoying notifications or scam ads, users can follow a few simple recommendations:

• Where possible, block all subscription offers, unless they come from popular and trusted websites. Remain vigilant to ensure you are not redirected to a fake website.
• If you’re unable to avoid an unwanted subscription, block it in the browser settings.
• Start using a reliable security solution, like Kaspersky Security Cloud, that blocks ad and scam push subscription offers in browsers, can delete subscriptions that have already been approved, and has an anti-phishing feature.

Read more on the topic in the Kaspersky Unwanted Notifications report on Securelist.